The presently disclosed subject matter relates to an airway adaptor which is attached to the face of the subject to collect the exhalation, and also to a system for acquiring various kinds of biological information by using the airway adaptor.
There is a system for acquiring the concentration of carbon dioxide contained in the exhalation of the subject, as an example of biological information. JP-A-8-233806 discloses a biological information acquiring system in which light-emitting and light-receiving elements that function as a part of a carbon dioxide sensor are attached to an airway adaptor. A gas passage provided in the airway adaptor extends so as to cross the space between the light-emitting and light-receiving elements, and the exhalation of the subject directly flows into the gas passage.
The light-emitting element emits light which is absorbed by carbon dioxide (for example, infrared light). The intensity of light which reaches the light-receiving element differs depending on the concentration of carbon dioxide contained in the exhalation of the subject. When a signal which is output from the light-receiving element, and which corresponds to the intensity is monitored, therefore, it is possible to acquire the concentration of the carbon dioxide.
As another example of biological information, there is a system for acquiring the arterial oxygen saturation (SpO2) of the subject. The arterial oxygen saturation is an index indicating the amount of oxygen which is supplied into the blood. JP-A-2007-54594 discloses a biological information acquiring system in which light-emitting and light-receiving elements that function as a part of an arterial oxygen saturation sensor are opposed to each other across the fingertip of the subject.
The light-emitting element emits red and infrared light beams. The intensities of light beams which reach the light-receiving element differ depending on the ratio of hemoglobin combined with oxygen in the blood. When a signal which is output from the light-receiving element, and which corresponds to the intensities is monitored, therefore, it is possible to acquire the arterial oxygen saturation.
A further example of biological information to be acquired is the respiratory volume of the subject. As a method of acquiring the respiratory volume, there is a method in which a tube connected to a pressure sensor is attached to the nostril or mouth of the subject, and a pressure variation in the tube which is produced by respiration is detected by the pressure sensor.
As described above, in order to acquire various kinds of biological information, devices which correspond to respective kinds of biological information, such as a sensor element and a tube must be attached to various places of the body of the subject. Therefore, the attaching work requires much labor, and the subject to whom many devices are attached feels strong botheration.